[PATCH v2] xen-blkback: replace work_pending with work_busy in purge_persistent_gnt()

[Bob Liu <bob.liu@oracle.com>]

The BUG_ON() in purge_persistent_gnt() will be triggered when previous purge
work haven't finished.
There is a work_pending() before this BUG_ON, but it doesn't account if the work
is still currently running.

Signed-off-by: Bob Liu <bob.liu@oracle.com>
---
Change in v2:
 * Replace with work_busy()
---
 drivers/block/xen-blkback/blkback.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index ced9677..954c002 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -369,8 +369,8 @@ static void purge_persistent_gnt(struct xen_blkif *blkif)
 		return;
 	}
 
-	if (work_pending(&blkif->persistent_purge_work)) {
-		pr_alert_ratelimited("Scheduled work from previous purge is still pending, cannot purge list\n");
+	if (work_busy(&blkif->persistent_purge_work)) {
+		pr_alert_ratelimited("Scheduled work from previous purge is still busy, cannot purge list\n");
 		return;
 	}
 
-- 
1.7.10.4